1. Field of the Invention.
This invention relates to a clamp for use in, for example, tension and compression testing machines and more particularly to a clamp useful to prestress the joint between a grip which holds the workpiece being tested and the piston rod connected to the actuator which applies the compression and tension forces.
2. Description of the Prior Art.
Tests involving repeated applications of stress, called fatigue tests, are usually performed by cyclic compression and tension. Examples of machines used in fatigue tests may be seen in the M. M. Gram U.S. Pat. No. 3,320,798 assigned to the assignee of the present invention. As can be seen in this patent, a reciprocating actuator operates to cyclically move an actuator rod or shaft back and forth. The actuator rod is connected to a grip device which is operable to hold the specimen being tested. The grip device is connected to the actuator rod or shaft by means of a threaded connection between the grip and the actuator rod to hold the two together.
Other methods of joining the grip to the actuator rod are also usable. For example, a V-band coupling manufactured by Voss Industries, Inc., of Cleveland, Ohio, could encompass a pair of flanges extending radially out from the joining ends of the grip and actuator rod which would then be tightened to secure the two members together in a rigid manner.